CN112601654B

CN112601654B - Method for printing and manufacturing sensor

Info

Publication number: CN112601654B
Application number: CN201880096839.6A
Authority: CN
Inventors: 李长鹏; 陈文曲; 陈国锋
Original assignee: Siemens Ltd China
Current assignee: Siemens Ltd China
Priority date: 2018-09-13
Filing date: 2018-09-13
Publication date: 2023-01-31
Anticipated expiration: 2038-09-13
Also published as: EP3835033A1; CN112601654A; EP3835033A4; WO2020051843A1

Abstract

A method of printing a sensor, comprising the steps of: s1, paving first powder in a forming cylinder (130) of a binder spray forming device (100), and carrying out glue spraying printing from bottom to top according to a sensor model to form a sensor shell (20) with a top opening and a first containing space in the middle and a containing cavity (22) arranged in the sensor shell (20); s2, paving second powder in a forming cylinder (130) of the adhesive spray forming device (100), and carrying out glue spraying printing from bottom to top according to a sensor model to form a sensor (24); s3, lifting the accommodating cavity (22) from bottom to top, and recovering the first powder in the accommodating cavity (22); s4, putting the sensor (24) into the sensor shell (20), and removing glue in the sensor (24) and the sensor shell (20); step S5, a sintering process is performed on the sensor (24) and the sensor housing (20) to form the sensor element (200, 300). The method for printing the sensor has lower manufacturing cost and higher efficiency.

Description

Method for printing and manufacturing sensor

Technical Field

The present invention relates to additive manufacturing technology, and in particular to a method of printing a manufactured sensor.

Background

Additive Manufacturing (Additive Manufacturing) is one of the important 3D printing technologies, and can rapidly manufacture a pre-designed CAD model and manufacture a component part with a complex structure in a short time. A Selective Laser Melting (SLM) process is one of Additive manufacturing (Additive manufacturing) technologies, which can rapidly manufacture the same parts as a CAD model by means of Laser sintering. Currently, selective laser melting processes are widely used. Unlike conventional material removal mechanisms, additive manufacturing is based on a completely opposite material additive manufacturing concept (materials additive manufacturing philosophy), where selective laser melting utilizes high power lasers to melt metal powders and build parts/components layer by layer through 3D CAD input, which can successfully manufacture components with complex internal channels.

An additional particular advantage of additive manufacturing is also the manufacture of components with hybrid structures, such as embedded sensors. However, due to the high melting temperature of the additively manufactured metal powder, the embedded sensor may over-temperature fail at the high intensity laser power of the additively manufactured molten metal powder. This is because the sensor is generally a semiconductor device, and cracks or composition changes occur when the material is too cold or too hot. If a selective laser melting process is required to print the sensor, heat insulation can be well done, but the technical difficulty of arranging the heat insulation plate is high, and good sealing performance is also ensured, so the technical scheme is still in a theoretical stage at present and is not realized actually.

There is no such hybrid structure of polymer or low melting temperature metal fabricated components that are currently available in the additive manufacturing field.

Disclosure of Invention

The invention provides a method for printing a sensor, which comprises the following steps: s1, paving second powder in a forming cylinder of a binder spray forming device, and performing glue spraying printing from bottom to top according to a sensor model to form a sensor; s2, paving first powder in a forming cylinder of the adhesive spray forming device, and spraying glue and printing from bottom to top according to a sensor model to form a sensor shell with a top opening and a first containing space in the middle and a containing cavity arranged in the sensor shell, wherein the containing cavity is provided with the top opening and a second containing space; s3, lifting the accommodating cavity from bottom to top, and recovering the first powder in the accommodating cavity; s4, putting the sensor into the sensor shell, and removing the glue in the sensor and the sensor shell; and S5, performing sintering treatment on the sensor and the sensor shell to form the sensor element, and removing glue in the sensor and the sensor shell by adopting a chemical dissolving or heating decomposition method.

Further, step S1 and step S2 are executed simultaneously or sequentially.

Furthermore, the side wall of the accommodating cavity is also provided with a plurality of holes or slots.

Further, the thickness of the sensor shell is larger than that of the accommodating cavity.

Further, the first powder is ceramic powder or metal powder, and the second powder is ceramic powder or metal powder.

Further, the first powder and the second powder are different ceramic powders or metal powders.

Further, the apparatus for performing sintering in step S5 includes a high temperature furnace, an atmosphere furnace, and a vacuum furnace.

Further, the step S4 further includes the following steps: after the sensor is placed in the sensor shell, first powder is continuously paved in a forming cylinder of an adhesive injection forming device, glue spraying printing is carried out from bottom to top according to a sensor model, and an upper cover part of the shell is continuously formed on the buffer layer to form a closed sensor shell with a first accommodating space.

Further, in the step S1, the method further includes the steps of: and coating conductive electrode slurry on the upper surface of the sensor.

Further, in the step S2, the method further includes the following steps: the sensor housing is provided with a conductive slot.

The advantage of using the binder injection molding device for manufacturing the sensor element is that the binder injection molding device does not use a high-energy beam, which is expensive, and power consumption is reduced. Meanwhile, the print head can be combined with thousands of nozzles, and thus can be accelerated more than a general 3D printing apparatus. Moreover, the adhesive injection molding apparatus is more suitable for manufacturing sensor elements printed mainly from ceramic and metal powders, so that the method of printing a sensor using the present invention can greatly expand the throughput.

The invention can directly manufacture the element with the embedded structure through an additional sintering process without arranging an additional welding process.

The invention can ensure that the manufactured sensor shell has good mechanical strength, wherein the sensor shell and the sensor have contact stability. In addition, the sensor element manufactured by the present invention has good functional performance. The invention can also allow sensors and cases with internal configurations to have complex shapes (complex shape) and high flexibility (high flexibility).

Drawings

FIG. 1 is a schematic view of the construction of an adhesive spray forming apparatus provided by the present invention;

fig. 2A-2C are process flow diagrams of forming a sensor element using an adhesive injection molding apparatus according to an embodiment of the present invention.

Detailed Description

The following describes embodiments of the present invention with reference to the drawings.

The invention provides a new additive manufacturing process adopting a binder injection molding (binder injection) technology with low cost. By the method provided by the invention, the element shell and the embedded sensor can be sintered at the same time, and the element can achieve good mechanical performance and function.

The invention provides a method for printing a sensor, which utilizes a 3D printing technology of adhesive spray forming to respectively form a sensor and a shell thereof in a sensor element.

Fig. 1 is a schematic structural view of an adhesive injection molding apparatus provided by the present invention. The binder spray forming technique utilizes a laser sintering technique and uses a powder bed. Wherein, the ink-jet printing head sprays adhesive into a material (usually powder) for 3D printing, so that the powder not only is adhered to itself but also is combined with the previous powder material layer in a penetration way, and the powder material layer is superposed layer by layer to form a prototype, and then the adhesive is removed by high-temperature sintering (sintering) and the fusion and connection of powder particles are promoted, thereby obtaining a 3D printing piece with ideal density and strength. The adhesive spray forming technology is suitable for printing metal and ceramic materials. As shown in fig. 1, the adhesive injection molding apparatus 100 includes a liquid adhesive supply apparatus 110, a powder feeding cylinder 120, a molding cylinder 130, and a spray head 140. A first piston 122 is disposed below a space where the powder feeding cylinder 120 accommodates the printing powder, the printing powder can be lifted up integrally along with the vertical movement of the first piston 122 from bottom to top, and then the upper roller 124 rolls through the left and right planes thereof to feed the printing powder into the forming cylinder 130. A second piston 132 is also disposed below the powder bed 134 of the forming cylinder 130, and the second piston 132 moves from top to bottom during 3D printing to form a printing space in the forming cylinder 130. The liquid binder supply device 110 is used for supplying liquid binder to the spray head 140, and the spray head 140 sprays the binder into the printing powder of the powder bed 134, so that the powder is bonded and infiltrated together through the binder and is stacked layer by layer from bottom to top to form the 3D prototype. The prototype in which the binder injection molding technique has been formed is not yet sintered, corresponding to a blank formed according to a 3D printing model.

It should be noted that the adhesive injection molding technology has the advantages of being capable of printing a plurality of same original parts from bottom to top, and having higher efficiency and stronger controllability.

According to an embodiment of the present invention, first, in step S1, the second powder is spread into the forming cylinder 130 of the binder injection molding apparatus 100, and the glue is sprayed and printed from bottom to top according to the sensor model, so as to form a sensor 24 as shown in fig. 2A to 2C. Specifically, the powder bed 134 is filled with a second powder (not shown), which is a metal powder, in the forming cylinder 130 of the binder injection-molding apparatus 100. The spray head 140 sprays a binder into the second powder of the powder bed 134, so that the second powder penetrates together by means of the binder and forms the prototype of the sensor 24 in a stack from bottom to top.

Then, step S2 is performed, the first powder is spread into the forming cylinder 130 of the adhesive injection molding device 100, and the adhesive printing is performed from bottom to top according to the sensor model, so as to form the sensor housing 20 with a top opening and a first accommodating space in the middle and the accommodating cavity 22 arranged in the sensor housing 20, wherein the accommodating cavity 22 has a top opening and a second accommodating space 22a. As shown in fig. 2A, the illustrated arrow direction Z indicates this printing direction, i.e., a vertically bottom-up direction. Specifically, the powder bed 134 is filled with a first powder, which may be a ceramic powder or a metal powder, in the forming cylinder 130 of the binder spray forming device 100. The spray head 140 sprays the adhesive into the first powder of the powder bed 134, so that the first powder is bonded and infiltrated by the adhesive and is stacked layer by layer from bottom to top to form a prototype of the sensor housing 20 and a prototype of the receiving cavity 22.

It should be noted that the prototype of the sensor housing 20 and the prototype of the receiving cavity 22 are not sintered, but are bonded together by spraying glue, which is equivalent to a blank.

Wherein the sensor housing 20 prototype is typically a "wellhead" shape with a high peripheral height and a concave center, but with a greater thickness. In particular, the prototype housing cavity 22 is also typically in the shape of a "well head" with a high peripheral height and a concave center, but with a small thickness compared to the thickness of the sensor housing 20. The accommodating cavity 22 is sleeved in the sensor housing 20, and the first powder is provided between the sensor housing 20 and the accommodating cavity 22. At the same time, the accommodating chamber 22 is also filled with the first powder.

The sensor housing 20 and the receiving cavity 22 may have a shape that is recessed in the middle thereof with a receiving space in the middle and opened upward, as long as the height of the outer periphery is high. The sensor housing 20 may be formed to accommodate the accommodation chamber 22 at a predetermined distance. In addition, the housing chamber 22 also houses the sensor. Accordingly, the shapes of the sensor housing 20 and the receiving cavity 22 may be selected according to the specific application scenario.

In particular, the thickness of the sensor housing 20 is greater than the thickness of the receiving cavity 22.

Wherein the first powder is metal powder or ceramic powder, and the second powder is metal powder. When the first powder and the second powder are both metal powders, they may be different types of metal powders.

It should be noted that the prototype of the sensor 24 is not sintered, but is bonded together by spraying glue, and corresponds to a blank.

It should be noted that, in the above embodiment, the step S1 and the step S2 are respectively executed according to a sequence, that is, the step S1 is executed first, and then the step S2 is executed. Alternatively, step S2 may be performed first, and then step S1 may be performed. The steps S1 and S2 may also be performed simultaneously, i.e. in different binder injection molding devices. That is, step S1 and step S2 do not necessarily have a sequential order.

Next, step S3 is executed, so that the accommodating cavity 22 is lifted from the bottom as shown in fig. 2A, and the first powder in the accommodating cavity 22 is also carried away from the bottom to the top along with the accommodating cavity 22. In this way, the first powder in the housing chamber 22 is not used and can be recovered and recycled. Therefore, the present invention also has the advantages of environmental protection and low cost.

Note that the first powder between the sensor housing 20 and the accommodation chamber 22 remains in the sensor housing 20. Even the first powder in the containing cavity 22 cannot be completely carried away and recovered, and remains in the sensor housing 20. And, during the process of lifting up the accommodation chamber 22 from below, the first powder therein also falls into the sensor housing 20. The first powder residue does not have a negative effect and can act as a buffer between the subsequent sensor 24 and the sensor housing 20 to improve the stability of the sensor within the sensor housing.

Step S4 is then performed, as shown in fig. 2B, to place the sensor 24 into the sensor housing 20 with the first powder remaining from step S2 between the sensor housing 20 and the receiving cavity 22 to act as a buffer layer 26. Specifically, after the sensor 24 is placed in the sensor housing 24, the first powder is spread in the forming cylinder 130 of the adhesive injection molding device 100, and the adhesive is sprayed and printed from bottom to top according to the sensor model, and the housing upper cover portion is formed on the upper surface of the cushioning layer 26 and the upper surface of the sensor housing 20, so as to form the closed sensor housing 20 having the first accommodating space. Before sintering is performed, the glue in the sensor 24 and the sensor housing 20 may be removed by chemical dissolution or thermal decomposition, depending on the type of glue used.

Finally, step S5 is performed to perform a sintering process on the prototype sensor 24 and the prototype sensor housing 20 to form the sensor element 200. Specifically, the apparatus for performing sintering includes a high temperature furnace, an atmosphere furnace, and a vacuum furnace. In particular, in order to obtain high density and suitable mechanical strength (acceptable mechanical strength), the temperature ranges from 1000 ℃ to 1300 ℃ for 316L (stainless steel material) or In718 (superalloy material) and In625 (superalloy material), which is close to the sintering temperature of functional materials, such as PZT ceramics and thermoelectric (thermomechanical) CaMnO ₃ Wherein, the sintering temperature of the PZT ceramic ranges from 1120 ℃ to 1200 ℃, and thermoelectric CaMnO is adopted ₃ The temperature range of (a) is less than 1200 ℃. Preferably, the one-time sintering process can also be optimized by adjusting the suitable sintering temperature for the sensor housing material and the sensor material, respectively, so that the adjustment of the particle size dimension can be controlled.

The finished sensor element 200 shown in fig. 2B is made according to the method described above. According to another variation of this embodiment, the present invention can also sinter the metal powder between the sensor housing 20 and the accommodating cavity 22 into the dense material layer 28, thereby forming the sensor element 300 as shown in fig. 2C.

Preferably, the side wall of the accommodating cavity 22 further has a plurality of holes or slots 22a. Therefore, when the accommodating chamber 22 is lifted up from the bottom in step S3, the first powder may fall into the first accommodating space of the sensor housing 20 through the hole or the slot 22a so as to serve as a buffer layer.

Further, in the step S1, the following steps are further included: and coating conductive electrode slurry on the upper surface of the sensor. Such a conductive electrode paste coating is required to act as an electrode if it is desired to provide an electrode on the sensor, particularly when the sensor material is ceramic. Preferably, the present invention selects platinum electrode paste as the conductive electrode paste coating layer to serve as an electrode, and thus is sintered together in the sintering step S2 without two separate steps.

Accordingly, in order to engage the electrodes on the sensor, the sensor housing is provided with a conductive groove. This is because the electrodes need to be drawn out, and therefore the conductive grooves are used to draw out the electrodes on the sensor for connection.

The invention can ensure that the manufactured sensor shell has good mechanical strength, wherein the sensor shell and the sensor have contact stability. In addition, the sensor element manufactured by the present invention has good functional performance. The invention can also allow sensors and cases with internal construction to have complex shapes (complex shape) and high flexibility (high flexibility).

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be limited only by the attached claims. Furthermore, any reference signs in the claims shall not be construed as limiting the claim concerned; the word "comprising" does not exclude the presence of other devices or steps than those listed in a claim or the specification; the terms "first," "second," and the like are used merely to denote names, and not any particular order.

Claims

1. A method of printing a sensor, comprising the steps of:

s1, paving second powder in a forming cylinder (130) of a binder spray forming device (100), and performing glue spraying printing from bottom to top according to a sensor model to form a sensor blank;

s2, paving first powder in a forming cylinder (130) of the adhesive spray forming device (100), and performing glue spraying printing from bottom to top according to a sensor model to form a sensor shell (20) with a top opening and a first containing space in the middle and a containing cavity (22) arranged in the sensor shell, wherein the containing cavity (22) is provided with a top opening and a second containing space;

s3, lifting the accommodating cavity (22) from bottom to top, and recovering the first powder in the accommodating cavity (22);

s4, putting the sensor blank into the sensor shell (20);

s5, performing sintering treatment on the sensor blank and the sensor shell (20) to form a sensor element (200, 300), and removing glue in the sensor element (200, 300) by adopting a chemical dissolving or heating decomposition method;

the first powder is ceramic powder or metal powder, and the second powder is ceramic powder or metal powder.

2. The method of printing a sensor according to claim 1, wherein steps S1 and S2 are performed simultaneously or sequentially, respectively.

3. The method of printing a sensor according to claim 1, wherein the side wall of the receiving cavity (22) further has a plurality of holes or slots (22 a).

4. The method of printing a sensor according to claim 1, wherein the thickness of the sensor housing (20) is greater than the thickness of the receiving cavity (22).

5. The method of printing a sensor of claim 1, wherein the first powder and the second powder are different ceramic powders or metal powders.

6. The method of printing a sensor according to claim 1, wherein the means for performing sintering in step S5 comprises a high temperature furnace, an atmospheric furnace, a vacuum furnace.

7. The method of printing a sensor according to claim 1, wherein said step S4 further comprises the steps of:

after the sensor blank is placed into the sensor shell (20), the first powder is continuously paved in a forming cylinder (130) of an adhesive injection forming device (100), glue spraying printing is carried out from bottom to top according to a sensor model, and the upper cover part of the shell is continuously formed on the buffer layer (26) to form the closed sensor shell (20) with the first accommodating space.

8. The method of printing a sensor according to claim 1, further comprising, in the step S1, the steps of:

and coating conductive electrode slurry on the upper surface of the sensor blank.

9. The method of printing a sensor according to claim 1, further comprising, in the step S2, the steps of:

the sensor housing (20) is provided with a conductive groove.